> <compilers@is-not-my.name>> With respect to the danger of implicit declarations in Fortran, there are> plenty of stories of broken code due to statements like DO 10 I = 1.10> which is an assignment, not a loop. -John]

This kind of thing has more to with a poor syntax rather than implicit
declarations.

The old (orignal syntax) of FORTRAN permitted spaces anywhere (or none
of them) because spaces were ignored [except in strings].

Had spaces been significant, DO 10 I would have been parsed as three
separate tokens. As it was, FORTRAN parsed it as the single token
"DO10I", which was a legal identifier.
[That's an egregious example, but I've written plenty of buggy code where
I spelled a variable name in two ways. Not really a compiler issue, though,
since it's easy enough to implement either way. -John]